The contractor serves as a general Vaccine and Treatment Evaluation Unit for the Enteric Diseases Branch, DMID, NIAID. Phase I and II clinical studies will be performed in adult (including elderly), adolescent, and pediatric groups consisting of normal and "at risk" individuals. Responses to vaccines including combinations, new adjuvants, live vectors as well as antivirals and other prophylactic and therapeutic interventions will be studied. Safety, immune responses, correlates of immunity will be analyzed. Examples of vaccines to be studied include, but are not limited to: rotavirus, hepatitis A, Herpes simplex type II, influenza, Bordetella pertussis, Haemophilus influenzae type B, Neisseria meningitidis, Streptococcus pneumonia, and Group B streptococci, respiratory syncytial virus, and parainfluenza virus. In addition to clinical trials, limited epidemiologic surveillance studies will be performed to determine the presence of infectious disease agents and the disease caused by them to help in the design of prevention studies and to understand infection/disease. There is a possibility that Phase III studies will be initiated if the attack rate warrants a study at this site. Multicenter trials involving one or more of the other Vaccine and Treatment Evaluation Units may be initiated as well.